IMSP

IMSP (Internet Message Support Protocol) is a device that was proposed to support medium to large scale institutions. IMSP is intended as a complement to IMAP in that it uses the same server/client relationship where everything is stored in a single location.

IMSP is designed to hold client preferences, extended mailbox information, and address books. It does this by running a service on a central server, not necessarily the IMAP server itself, and listens on TCP/IP port 406.

IMSP server/client communications look a lot like IMAP communications. The login syntax is the exact same, and many of the commands accept syntax in a similar format.

IMSP was designed by Project Cyrus at Carnegie Mellon University (CMU) but has no reached RFC level. Because of the complexity involved in achieving a RFC, the IMSP project has no wish at this time to become an official RFC.

One of the few clients to provide full IMSP integration is Cyrusoft’s Mulberry Email Client. Mulberry is designed to run on the Apple Macintosh, x86 based Windows PCs, and Linux. There is also a web-based product called SilkyMail that is a hacked version of IMP’s webmail product to include IMSP support.